Single-use or disposable systems are rapidly increasing in biopharmaceutical industry due to the flexibility and cost-effectiveness of such systems. Disposable components in the systems are presterilized and qualified to regulatory requirements. Disposable systems are easy to adapt to different production purposes and it is easy and inexpensive to change a product line while good process reliability is at least maintained or even improved.
There are several kinds of biopharmaceutical systems, such as mixing systems, in which disposable containers or bags may be used. These containers or bags are made of sheets of flexible material, such as plastic, plastic laminates or corresponding materials.
One type of mixing systems in which such containers can be used is a bioreactor system in which cells or microorganisms can grow. Mixing systems include also systems used to prepare for example buffer and media.
Mixing systems may comprise a support or vessel which supports or houses a disposable bag or container of the above-mentioned type. The support may be a support plate or tray for a bioreactor bag of a kind used in GE Healthcare WAVE BioreactorTM systems. The vessel may be a tank-type support which has a substantially cylindrical form, for example substantially circular cylindrical and is made of rigid material such as stainless steel to provide sufficient support for a flexible bag or container. The flexible container or bag is placed on the tray or in the inside of the vessel in an accurate manner so that for example different pipelines or tubes, mixers and sensors can be connected to the bag properly and accurately. US2011/0310696 and EP1842800 disclose mixing systems of this kind
As mentioned above, disposable containers are often mainly made of sheets of flexible materials. To stabilize or reinforce the containers or to enable the connection of different pipelines or sensors to the containers they may comprise parts of rigid or semi-rigid materials. These rigid or semi-rigid parts provide a platform for safe and secure attachment of for example sensors, pipelines for fluids (both gas and liquid) and mixers. Further, the rigid or semi-rigid parts can reinforce and stabilize the containers and therefore facilitate placing of the containers into mixing vessels in accurate manner.
However, seals between rigid/semi-rigid and flexible materials may involve a safety risk, since the seals may be weak and thereby cause leakage of the liquids in the container and/or contamination of the liquids inside the container by the surrounding environment. Therefore, it is essential that the risk for leakage and/or contamination can be minimized and the seal between these different materials can be made as safe and secure as possible.
Containers may vary in size from about 1 liter to about 2000 liters and especially, if containers are large and leakage occurs from the material seals, there may be catastrophic consequences both in respect of loss of material and consequences to the surrounding environment, since the liquids leaked may cause damage to the surrounding equipment, such as control computers. Of course, the leaked liquid has to be cleaned which is both expensive and labour consuming.
Another problem which may occur in the seals of traditional type is micro leakage, i.e. leakage in very small amounts which is due to the unevenness of the sealing. Micro-leakage may cause contamination of sensitive cultivations and also on the other hand the environment surrounding the cultivation.